Optimization of the Technology of Steel Casting Reinforcement by Hard Alloys with the Use of Computer Modeling
Tech Area / Field
- MAN-COM/CAD and CAM/Manufacturing Technology
3 Approved without Funding
Central Research Institute for Materials, Russia, St Petersburg
- All-Russian Scientific Research Institute of Non-Organic Materials named after A. Bochvar, Russia, Moscow
- Korea Institute of Machinery&Materials, Korea, Changwon\nCaterpillar Inc., USA, IL, Peoria
Project summaryAim of the Project – the increase of working capacity of cast parts, operated under impact abrasion, by local reinforcement of loaded areas by Hard Alloys.
Steel cast machine parts operated under impact abrasion are widely used in mining and reprocessing industries. Among these parts there are excavator teeth, grinding parts of crushers, boring chisel bodies, various components of road-building machines, dredges, coal-mining machines etc. In most of the cases, such castings are manufactured from high-manganese Gadfield Steel that operates satisfactorily only on condition that deformation hardening takes place, i.e. under conditions of impact loading, but shows low operating capacity at the presence of abrasion. Besides, melting of Gadfield steel is interlinked with worsening ecological situation in foundry shops.
In some cases, the problem of increasing working capacity is solved by fusing abrasion-resistant covers onto the loaded surfaces of parts with the use of special electrodes. However, the fusing practice is highly labor-consuming, and it does not always provide necessary quality, because of origination of thermal stresses, deformities and cracks.
The present Project provides for creation of a new foundry technology of superficial and local-volume reinforcement of castings in areas subjected to impact abrasion in operation. It is suggested to create both a technology of direct reinforcement of castings and a technology of manufacture of steel reinforced components attached to loaded surfaces of parts by welding.
The essence of the technology suggested is the following: reinforcing components manufactured from Hard-Alloy scrap – worked-out armor-piercing cores, used-up cutting plates, boring-chisel teeth and grit produced by grinding lump scrap – are placed into a casting mold. After pouring of liquid steel into a mold, a composite layer reinforced with Hard Alloy is formed in the loaded areas of a casting, that substantially increases operating capacity of parts.
For formation of high-quality reinforced layer in a casting, it is important to provide optimum thermal and diffusive interaction of liquid metal with reinforced components, that will be solved with the use of computer modeling of the processes of pouring, solidification and reciprocal diffusion of cast metal and Hard-Alloy components. The use of computer modeling of thermal, shrinkage and diffusion processes brings wide opportunities for optimization of steel-casting reinforcement practice.
The scope of work on the present Project suggests solution of the following problems:
– development of typical schemes of casting reinforcement and unification of reinforcing components, according to their geometry and size;
– improvement of the physical and mathematical models and software for computer modeling of casting formation with the use of different reinforcement schemes;
– development of the pouring technology based on computer modeling;
– investigation of structure and properties of reinforced layer depending on temperature and duration of contact between liquid metal and Hard Alloy;
– creation of a laboratory stand for estimation of abrasion resistance of cast reinforced samples under conditions of various proportions between impact and abrasion loadings;
– manufacture and tests of a representative lot of reinforced abrasion-resistant parts;
– development of measures for commercialization of the Project results.
The results of work will have scientific, technical and commercial aspects.
A scientific aspect will include:
– creation of a physical and mathematical model of thermal and diffusive interaction of liquid metal with Hard Alloy;
– research of these processes by means of optical metallography and electron microscopy and estimation of adequacy of the suggested and utilized model.
A technical aspect will be directly presented by the developed technology of manufacture of castings reinforced with Hard Alloy, that provides three-five times’ increase of their operating capacity under conditions of impact abrasion.
A commercial aspect is a profit receipt on account of the increase of working time of parts as well as the decrease of costs connecting with stopping machines and aggregates for replacement of worn-out parts.